Spelling suggestions: "subject:"fossils"" "subject:"fòssils""
111 |
Virtual reconstruction of stratigraphy and past landscapes in the West Coast Fossil Park region /Erasmus, Lelandi. January 2005 (has links)
Thesis (MA)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.
|
112 |
Transformace / TransformationZAPLETALOVÁ, Petra January 2013 (has links)
Abstract The thesis consists of two parts: theoretical and practical. In the theoretical part of my thesis I would like to describe the development of art, especially the prehistoric times, the specifics of the time and gradual changes, focusing on the life of prehistoric creatures and their development. Zoom personalities related to this topic, especially illustrators, painters, filmmakers, who are involved in public awareness about the picture of the time. Finally, I would like to mention the influence of authors and styles of the 20th century and approached the work of contemporary artists inspired by this theme. In the practical part of the thesis, deals with the presentation selected and died out creatures. To this I would like to take the theoretical and practical knowledge based on my work involved.
|
113 |
Stone exposures : a cultural geology of the Jurassic CoastFerraby, Rose January 2015 (has links)
People have varied and complex relationships with stone, in its raw geology and in its altered forms. Often, however, in cultural contexts, stone remains in the background, as a taken for granted and unremarkable element of the material world. In this thesis, stone moves into the foreground. The research presented here explores how close attention to those who work intimately with stone can disclose unexpected and absorbing stories. The cultural geologies extracted and presented in this thesis cast light on the diversity of ways in which people relate to, and with, the land; and experiment with a range of different ways in which these relations can be narrated. Set on the Jurassic Coast, in the south west of England, the stone exposures that emerge along the margin between land and sea offer a productive site for developing a cultural geological approach. The limestones, shales and clays are framed, in this work, by the narratives of quarrymen and geologists. The work explores how their particular knowledges are formed, and how they exist within wider historical and ecological understandings. Their narratives bring the stratigraphy to life, and draw attention to the hidden worlds within it. The different priorities and perspectives of quarrymen and geologists are shown to lead in different directions, interweave, or run parallel. The very specific languages and descriptions they employ reveal a level of complexity and richness of detail that is mirrored in the stone. Using an approach that combines close observation and creative practice, this study examines stone at a variety of scales, and in different contexts. The work engages with specific stone types, landscapes, voids, buildings and objects. Processes of working stone through practices of lettering, sculpture and masonry elicit understandings of the material that reach far beneath its surface. The absent spaces of quarries are then explored, showing how voids can be animated with knowledge, and how destructive processes can generate creative potential, when sensitively worked and considered. Lastly, the study draws all these ideas together in a discussion of stone assemblages in buildings, to see how voices from geology and quarrying can foster greater understanding of how buildings were constructed in the past, and how we conserve them into the future.
|
114 |
A taxonomic and taphonomic analysis of Late Jurassic horseshoe crabs from a Lagerstatte in central PolandTashman, Jessica Nichole 20 November 2014 (has links)
No description available.
|
115 |
Neoichnology of Tropical and Arid Burrowing Scorpions: Environmental Impacts on Burrow Construction and FormHouser, Skyler K. 05 June 2023 (has links)
No description available.
|
116 |
Sediment Histories: Early Mesozoic Ice and North American Pleistocene-Holocene DeglaciationChang, Clara Yunn January 2024 (has links)
We use sedimentary structures, fossil evidence, sediment petrophysical properties, and geochemistry to investigate past climate.
In the first two chapters, we outline a toolkit to identify the presence of ice rafted debris in lake sediments using a combination of grain size analysis, computed tomography and image analysis. We apply this toolkit to sediments from the early Mesozoic, paleo-Arctic Junggar Basin, and describe the first evidence of continental freezing from this time period. We also discuss characteristics of algae rafted debris; clusters of coarse sediment suspended in a fine sediment matrix can be deposited without freezing conditions and may be a confounding factor in the geological record.
In chapters three and four, we examine sediment cores from the coast of New York and the effects of sea level rise after the last deglaciation. New AMS radiocarbon dates from submerged terrestrial sediments on the US Atlantic continental shelf provide key constraints on the timing of marine transgression following the retreat of the Laurentide Ice Sheet. We use sediment elevation tables (SETs) and sediment cores to measure the accretion rate in a Hudson River tidal wetland to determine its vulnerability to sea level rise. We find that SETs overestimate accretion and underestimate vulnerability on timescales relevant to coastal flooding risk. Together, these chapters outline novel tools and approaches in imaging, geochemistry, and micro-stratigraphy broadly applicable for investigations on paleoclimate research through time and space.
|
117 |
An integrated approach to the taxonomic identification of prehistoric shell ornamentsDemarchi, B., O'Connor, Sonia A., de Lima Ponzoni, A., de Almeida Rocha Ponzoni, R., Sheridan, A., Penkman, K.E.H., Hancock, Y., Wilson, J. 17 May 2014 (has links)
Yes / Shell beads appear to have been one of the earliest examples of personal adornments. Marine shells identified far from the shore evidence long-distance transport and imply networks of exchange and negotiation. However, worked beads lose taxonomic clues to identification, and this may be compounded by taphonomic alteration. Consequently, the significance of this key early artefact may be underestimated. We report the use of bulk amino acid composition of the stable intra-crystalline proteins preserved in shell biominerals and the application of pattern recognition methods to a large dataset (777 samples) to demonstrate that taxonomic identification can be achieved at genus level. Amino acid analyses are fast (<2 hours per sample) and micro-destructive (sample size <2 mg). Their integration with non-destructive techniques provides a valuable and affordable tool, which can be used by archaeologists and museum curators to gain insight into early exploitation of natural resources by humans. Here we combine amino acid analyses, macro- and microstructural observations (by light microscopy and scanning electron microscopy) and Raman spectroscopy to try to identify the raw material used for beads discovered at the Early Bronze Age site of Great Cornard (UK). Our results show that at least two shell taxa were used and we hypothesise that these were sourced locally.
|
118 |
Taxonomia e contexto geológico da tafoflora da Ilha Dufayel, Ilha King George, Península AntárticaFisch, Fabiane 30 July 2009 (has links)
Submitted by William Justo Figueiro (williamjf) on 2015-07-03T13:29:29Z
No. of bitstreams: 1
32.pdf: 3411336 bytes, checksum: f358b7f3896f7cfa77f0e9df07d8de5c (MD5) / Made available in DSpace on 2015-07-03T13:29:29Z (GMT). No. of bitstreams: 1
32.pdf: 3411336 bytes, checksum: f358b7f3896f7cfa77f0e9df07d8de5c (MD5)
Previous issue date: 2009-07-30 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Restos de plantas são comuns em áreas do norte da Península Antártica, em níveis datados entre o final do Cretáceo e início do Neógeno, tanto nas bacias de retroarco, como nas regiões correspondentes ao arco e antearco da Península continental e ilhas adjacentes. Sua importância reside na possibilidade que oferecem de reconstituir os eventos paleoclimáticos e paleogeográficos regionais aí ocorridos como, por sua relação com as modernas floras da América do Sul e Australásia, para a compreensão dos aspectos envolvidos na origem e distribuição das floras austrais modernas. A ilha King George, a mais setentrional das ilhas Shetland do Sul, insere-se no contexto de antearco e suas sucessões e fósseis foram profundamente afetados pelos eventos tectônicos e magmáticos que marcaram sua gênese. O objetivo deste trabalho é o estudo da flora preservada na pequena ilha Dufayel, situada no interior da baía Admiralty, porção central da ilha King George, onde os níveis com fósseis ocorrem entre litologias vulcânicas com idades K-Ar entre 52 e 57 Ma. A tafoflora foi revista e abordada em termos de sua caracterização taxonômica e relação com as litologias, e comparada com as presentes em bacias próximas e nas bacias austrais, objetivando avaliar sua coerência com as idades absolutas propostas, dada a possibilidade de rejuvenescimento das litologias datadas por este método. O intervalo fossilífero é constituído por tufos e tufos lapilíticos, com aproximadamente 4 m de espessura, atribuídos a Formação Dalmor Bank, unidade basal do Grupo Dufayel Island. Nas 42 amostras analisadas foi possível identificar 20 distintas formas, discutidas em suas afinidades. A precária preservação, onde muitas vezes faltavam os caracteres marginais e as nervuras de ordem mais alta, foi possível seu agrupamento em morfotipos e a separação de seus caracteres arquiteturais. Atestam uma tafocenose dominada por Nothofagus de folhas micro-mesofílicas, acompanhado por tipos relacionados com as famílias Myrtaceae, inclusive da secção Leptospermoidea, Sapindaceae, Anacardiaceae, Monimiaceae, Lauraceae, Celastraceae e Malvaceae, estando ausentes os fetos e coníferas, comuns em outras paleoassembléias da ilha King George. Composicionalmente a paleoflora é comparável com àquelas da base da Formação La Meseta, na Subacia de James Ross e das bacias austrais do Chile e Argentina durante o Paleoceno Superior e Eoceno basal. São igualmente correlacionáveis as que se distribuem entre o Eoceno e o Mioceno da Nova Zelândia. Assim, comprova-se a idade Eoceno Inferior (Ypresiano) proposta pelos dados isotópicos. Florestas subtropicais a temperadas úmidas de composição similar crescem hoje na região de Valdívia no Chile, e em áreas do sul da Austrália e na Nova Zelândia, entre os 35o e 45º de latitude. Sugerem condições ambientais mais aquecidas para seu crescimento nas áreas da Península durante o Paleógeno, e sua posterior dispersão para o norte, quando os climas na Antártica se tornaram desfavoráveis. / Plant remains preserved in levels deposited between the end of Cretaceous to the beginning of Neogene are common in the northern Antarctic Peninsula areas, been found both in the marine and transitional paleonvironments of the back-arc basins and in the corresponding arc and fore-arc subareal environments from the continental Peninsula and adjacent islands. Those floras have a critical role in the establishment of the paleoclimate and paleogeographic events occurred in this strategic area of the Gondwana land and to the understanding of the origin and distribution of modern southern hemisphere vegetation. King George Island, the northernmost South Shetland Islands, was formed in a fore-arc geological context and their successions and fossil were deeply affected by tectonic and magmatic events that marked its genesis. In this work the taphoflora identified in a 4 meters tick tephra deposit intercalated in an expressive volcanic and aglomerate pile at Dufayel Island, central area of KGI, was reviewed and discussed in terms of their taxonomic affinities and relationship to lithologies. It is compared with other plant fossil assemblages knowing from expositions of the island, with those knowing from Antarctic Peninsula, and from other southern basins, looking for its consistency with the K-Ar absolute ages of 57 and 52 Ma proposed to the lower and upper lava beds, given the possibility of rejuvenation in age of the lithologies dated by this method. Forty two samples were analyzed showing only impressions of leaves from 20 different morphotypes, some of them capable of to be established in its taxonomic affinities. Overall leaf material shows a very poor preservation, where often lacks the marginal characters and venation of higher order, that incentivates their treatment by morphological groups and occasionally the proposition of familiar and generic relations. The taphocenosis shows to be dominated by micro to mesophilic leaves of Nothofagus, accompanied by types related with Myrtaceae, including the section Leptospermoidea, Sapindaceae, Anacardiaceae, Monimiaceae, Lauraceae, Celastraceae and Malvaceae. Conifers and ferns, common in other fossil assemblages of King George Island and suggested in the previous works with this flora were not confirmed. The composition of the paleoflora is comparable with those present in the lower levels of La Meseta Formation, at James Ross basin, and some other floras identified in the southern basins from Chile, Argentina, with a Lower Eocene age. Also corresponds to the assemblages found in New Zealand, during the Upper Paleocene until Miocene. Those data gives support to the Lower Eocene (Ypresian) age proposed by the absolute methods obtained in the volcanic associated lithologies. Subtropical to temperate humid forests with a comparable composition grows today in Valdivian region of Chile, between 35o and 45º of latitude, and in areas of southern Australia and New Zealand, over thin and volcanic soils, suggesting similar conditions for its growth in the Antarctic Peninsula area during the Paleogene. Their disjunct modern distribution and its dispersion to more northern land masses seem to be a result of the definitive breakup of Gondwanaland and the arriving of severe and cold climates.
|
119 |
Icnologia de depósitos marinhos rasos regressivos: um exemplo do permiano superior da Bacia do ParanáLima, João Henrique Dobler January 2010 (has links)
Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2015-07-06T13:35:47Z
No. of bitstreams: 1
JoaoLima.pdf: 3825056 bytes, checksum: 17bc443c02a042f3194ce14358ee935d (MD5) / Made available in DSpace on 2015-07-06T13:35:47Z (GMT). No. of bitstreams: 1
JoaoLima.pdf: 3825056 bytes, checksum: 17bc443c02a042f3194ce14358ee935d (MD5)
Previous issue date: 2010 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / CNPQ – Conselho Nacional de Desenvolvimento Científico e Tecnológico / PROSUP - Programa de Suporte à Pós-Gradução de Instituições de Ensino Particulares / Este estudo analisa e caracteriza a paleoicnologia dos depósitos da Formação Teresina aflorantes no Cerro Caveiras (Dom Pedrito, RS), com a intenção de refinar as interpretações paleoecológicas e paleoambientais existentes. A icnofauna dos depósitos analisados é composta por Bergaueria isp., Cochlichnus anguineus, Cruziana problematica, Diplocraterion isp., Diplopodichnus biformis, Helminthopsis isp., Lockeia siliquaria, Multina minima, Palaeophycus striatus, Palaeophycus tubularis, Planolites beverleyensis, Planolites montanus, Scolicia cf. plana, Teichichnus isp. e Thalassinoides isp. Esta assembléia foi dividida em duas suítes, uma delas sinalizando colonização em ambiente de água salobra e a outra reunindo estruturas que sugerem colonização em ambiente de água doce. Cinco fácies sedimentares foram descritas: (i) fácies de lamito; (ii) fácies de arenito fino com estratificação cruzada cavalgante; (iii) fácies de heterolito; (iv) fácies de arenito com estratificação cruzada acanalada e; (v) fácies de arenito fino a médio com estratificação cruzada hummocky (HCS) ou swalley (SCS). Estruturas sedimentares geradas por ondas dominam a sucessão e as associações de fácies sugerem deposição em zona de shoreface inferior/transição ao offshore. Feições geradas pela ação de correntes também são comuns. A recorrente substituição da suíte de água salobra pela suíte de água doce e a manutenção desta por mais tempo ao longo da sucessão indica significativo aporte de água doce no sistema. Esse padrão, aliado ao estabelecimento da suíte de água doce sempre após a deposição das fácies indicativas da ação de correntes sugere a influência de depósitos deltaicos na zona de shoreface inferior, em um contexto marinho raso restrito. Duas superfícies estratigráficas são sugeridas pela análise da icnofauna, uma co-planar (S1), composta por, pelo menos, uma superfície de erosão regressiva e uma superfície transgressiva, e uma de inundação (S2), que marca o momento de maior profundização e de maior teor de salinidade do sistema, na área de estudo. A integração dos dados icnológicos e sedimentológicos do Cerro Caveiras sugere que esta sucessão sedimentar possivelmente represente deposição em frentes deltaicas distais retrabalhadas por ondas. / This study analyzes and characterizes the paleoichnology of the Teresina Formation sedimentary rocks cropping out in Cerro Caveiras (Dom Pedrito, Rio Grande do Sul State, south of Brazil), aiming to refine the existing paleoecological and paleoenvironmental interpretations. The ichnofauna is composed of Bergaueria isp., Cochlichnus anguineus, Cruziana problematica, Diplocraterion isp., Diplopodichnus biformis, Helminthopsis isp., Lockeia siliquaria, Multina minima, Palaeophycus striatus, Palaeophycus tubularis, Planolites beverleyensis, Planolites montanus, Scolicia cf. plana, Teichichnus isp. and Thalassinoides isp., distributed in two main trace fossil suites, a brackish-water suite and a freshwater suite. Five sedimentary facies were described: (i) laminated or massive shale; (ii) fine-grained sandstone with climbing ripples; (iii) heterolithic deposits; (iv) trough crossstratified sandstone; and (v) hummocky and swalley cross-stratified sandstone. Wavegenerated structures predominates and facies associations suggest deposition in lower shoreface/offshore transition setting. Current-generated structures are also common. The recurrent replacement of brakish-water suite by freshwater suite and the maintenance of the last one for more time in the sedimentary succession suggest a significative input of freshwater into the marine zones. This pattern, and the fact that freshwater suite settlement always occur after the current-generated sandstone deposition suggest deltaic influence in the lower shoreface, in a restricted shallow sea context. Two stratigraphic surfaces should be inferred by trace fossil analysis: a co-planar surface (S1), composed of a regressive erosion surface and a transgressive surface, at least, and a flooding surface (S2), which marks the deepest and saltiest episode in the depositional system at the study area. The integrated analysis involving the ichnology and sedimentology of the Cerro Caveiras succession suggest that it possibly represents a distal expression of wave-dominated delta fronts.
|
120 |
Pequenos roedores holocênicos do nordeste do Rio Grande do Sul: Descrevendo comunidades e suas respostas ante as mudanças ambientais / Holocenic small rodents from northeastern Rio Grande do Sul: Describing communities and yours answers to environmental changesRoth, Paulo Ricardo de Oliveira 07 December 2018 (has links)
A preservação de remanescentes de pequenos vertebrados é um evento bastante raro porque é necessário que fatores químicos, físicos, geológicos e biológicos atuem para que frágeis ossos e dentes não sejam destruídos pela decomposição, intempéries e processos geológicos. Apesar de raros, os testemunhos deste tipo de fauna são encontrados em escavações em abrigos sob rocha do nordeste (NE) do Rio Grande do Sul (RS). Muitas espécies de micromamíferos são excelentes bioindicadores porque possuem diferentes exigências ambientais e muitas ocupam nichos bastante específicos. Os estudos destes testemunhos contribuem para o entendimento da evolução morfológica e da história biogeográfica dos grupos preservados. Noutra via, o reconhecimento de comunidades pretéritas possibilita a reunião de informações que auxiliam no entendimento da história ambiental e climática de uma região. Portanto, a disponibilidade de coleções de fósseis e semi-fósseis de comunidades de pequenos mamíferos representa uma oportunidade única para compreendermos a história do estabelecimento de atuais padrões biológicos, ecológicos, ambientais e climáticos. Com base nas amostras de comunidades pretéritas de pequenos roedores (<1Kg) do NE do RS, meus objetivos são: descrever a história holocênica do clima e paisagem que resultaram na heterogeneidade de ambientes vista hoje na região de estudo (Capítulo 1) bem como também apresentar como àquelas mudanças afetaram as comunidades de roedores ao longo dos últimos 6.200 anos (Capítulo 2); utilizar dados novos de variações ao longo do tempo de três fontes (isótopos, fauna e pólen) associando-as as hipóteses disponíveis de trabalhos em palinologia principalmente, para contar a história dos processos naturais que resultaram nas riquezas de pequenos roedores e de ambientes hoje vistas na transição leste ente Pampa e Mata Atlantica (Capítulo 3) e; investigar na morfologia de Pseudoryzomys do passado buscando encontrar sinais de adaptação frente as mudanças de ambiente e discutir se tais diferenças são suficientes para reconhecer nas populações extintas do sul uma nova espécie (Capítulo 4). Para caracterizar os hábitats atuais e pretéritos, emprego dados de literatura, amostragem em campo de dados fisionômicos e florísticos e amostras de solo (para avaliação isotópicas), para inferir que, nas terras baixas da bacia do Sinos, até 8.600 anos AP o clima devia ser ameno e relativamente úmido possibilitando um ambiente de mistura entre plantas C3 e C4; entre 8.600 e 6.900 anos AP altas temperaturas e, provavelmente intensa pluviometria levam a um rápido domínio de campos de vegetação C4; de 6.900 a 5.600 as temperaturas se tornam mais amenas e o clima se mantêm úmido fomentando os primeiros avanços de formações florestais pioneiras associadas a Mata Atlantica; após 5.600, sobretudo após 4.000 anos AP., as florestas do bioma Atlântico avançam sobre as áreas abertas e úmidas formando a paisagem em mosaico característica atual. Para descrever a diversidade pretérita, analisei 13.617 ossos (inteiros e fragmentados) de pós-crânio e 1.716 partes cranianas e dentes de pequenos roedores, cujas idades inferidas vão desde 6.200 antes do presente até o recente e identifiquei 30 táxons. Para a descrição da diversidade atual, amostrei sete sítios nos quais coletei cerca de 5 Kg pelotas de corujas (provavelmente o mesmo agente formador das amostras pretéritas), que resultaram em 1.595 fragmentos, que permitiram a identificação de 18 táxons distintos. Reunindo as amostras pretéritas e atuais, pude organizar um catálogo desta fauna, que reúne 33 táxons dentre os quais destaco cinco extintos localmente, Kunsia sp., Clyomys sp., Pseudoryzomys simplex, Necromys cf. obscurus e cf. Thalpomys e, uma totalmente extintas, Dicolpomys fossor. A fim de estabelecer cenários paleoclimáticos e descrever as alterações nestas comunidades ao longo do Holoceno (Cap. 3), eu integrei as informações sobre a diversidade de hábitats e de espécies no passado e no presente, a dados palinológicos e isotópicos, e pude estabelecer que, no geral, há razoável coerência entre os cenários de mudança paleoambientais estabelecidos em trabalhos polínicos com as interpretações que pude fazer a respeito daquelas mudanças a partir de analises de mudanças de comunidade de roedores e de oscilações isotópicas no solo. Como principal ressalva as hipóteses de mudanças Holocênicas na paisagem, argumento que toda a região de várzea entre os rios Taquari, Jacui, Caí, Sinos e Gravataí deve ter sido dominada por amplas áreas alagadas num cenário muito próximo ao Pantanal devido a presença entre os semifosseis de táxons de roedores que hoje prosperam nesse bioma e pela presença de Blastocerus dichotomus, o qual era predado por índios no RS e hoje possui uma população relictual na APA do Banhado Grande, RS. No Cap. 4 realizo uma abordagem relativamente inédita para Sigmodontinae onde verifico através de morfometria geométrica que o efeito de desgaste dentário é bastante diferente entre populações antigas e atuais de Pseudoryzomys e, associando analises morfológica lineares discuto que o conjunto de variações dever ter estreita relação com a \"tentativa\" da população a se manter ante a mudança de cenário e, consequentemente, de dieta. / Small vertebrate\'s remnants preservation is rather rare event because is needed that specific factors occur together (chemical, physical, geological and biological) to not destroy fragiles bones and teeth by decomposition, weather and geological processes. Nonetheless, the evidences of this type of fauna are quite frequently found at rock shelters excavations at Rio Grande do Sul (RS). Many micro mammals species have different environmental requirements and occupy specific niches therefore are considered excellent bioindicators. Studies of these testimonies contribute to understanding the morphological evolution and of biogeographic history of these preserved groups. In another way, knowing past communities allows gathering a lot of information that helps understanding environmental and climatic history of a place. Therefore, the availability of fossil and semifossil collections from past small mammals communities is a odd opportunity to improve the current biological understanding of ecological, environmental and climatic patterns established along of the history. This study intends to contribute knowledge about northeast RS and about your Holocene rodent fauna. Based on past samples from small rodent communities (<1kg). The objectives of this thesis are: describe the climate and landscape Holocene history which resulted in current heterogeneity of northeast of RS (Chapter 1) as well as show how climatic and environmental changes affected rodent communities over past 6,200 years (Chapter 2); Use new data of three sources variation over time (isotopes, fauna and pollen) associating mainly with available palynology studies in order to interpret the natural processes history which resulted in small rodent richness and present environments at Atlantic Forest and Pampa transitions (Chapter 3) and; investigate past Pseudoryzomys morphology in order to find adaptation signs in face of environment changes and discuss whether these differences are enough to distinguish a new species in the South´s extinct populations (Chapter 4). To characterize current and past habitats (Chapter 1) literature, fisionomic and floristic field sampling and soil samples (for isotopic evaluation) data are used to infer that in Sinos´s basin lowlands up to 8600 years BP the climate would be moderate and relatively wet allowing a mixing environment of C3 and C4 plants; between 8,600 and 6,900 years high temperatures and probably intense rainfall lead to a domain of C4 vegetation filds. From 6,900 to 5,600 years the temperature become milder and the climat remains humid enabling the first advances of pioneer forest formations associated with Atlantic Forest. After 5,600 years especially after 4,000 years BP Atlantic biomes forests advance on open and humid areas forming the current characteristic mosaic landscape. To describe past diversity (chapter 2), 13,617 post-cranial skeleton\'s bones and 1,716 cranial parts and rodent teeth were analyzed. These samples have a inferred ages range from 6,200 years to present and 30 taxa were identified. To current diversity description were sample seven sites and was collected about 5 kg of owl\'s pellets (probably same forming agent of past samples) which 1,595 fragments were found and 18 taxa were identified. Combining present and past samples, a fauna catalog could be organized which includes 33 taxa among there are five locally extinct species (Kunsia sp., Clyomys sp., . Pseudoryzomys simplex, Necromys cf. obscurus e cf. Thalpomys) and one totally extinct (Dicolpomys fossor). In order to establish paleoclimatic scenarios and describe the changes of these communities throughout the Holocene, information on habitat diversity, past and present species diversity, palynological and isotopic data has been integrated (Chapter 3) and it has been found that there are generally reasonable coherence between paleoenvironmental change scenarios established in previous pollen studies with the interpretations suggested by the new analysis results in rodent, pollinic and isotopic communities presented in this work. The main exception to hypotheses for Holocene changes in landscape are that floodplain region among Taquari, Jacui, Caí, Sinos and Gravataí rivers must have been dominated by wide flooded areas very similar with Pantanal due to nowadays semi fossils rodent taxa presence and Blastocerus dichotomus presence (which was predated by indigenous in RS and today has a relictual population in APA do Banhado Grande, RS). In Chapter 4 was made a relatively new approach, using geometric morphometry to study Sigmodontinae. The results present that the effect of dental wear is quite diferente between past and presente populations of Pseudoryzomys. Associating linear morphological analyzes the set of variations should have close relation with the population´s \"attempt\" of keep up with scenery change and, consequently, of diet changes.
|
Page generated in 0.0486 seconds